Exhaust manifold part numbers will not, by themselves, tell you if they are original. You need the date codes for that. The manifolds were usable for many year model cars, with few design changes, so the part numbers may not have changed for different year models. Some years, depending on equipment(A/C, PS, etc.) used the same manifold on both sides. Don't count on the "RH" and LH" actually meaning the manifold will only work on that side. If it fits, and functions properly, it's fine. If you plan on having the car judged, I still wouldn't worry about it....you can't really see all the numbers anyway, so it will be judged on appearance, for the most part.
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Joel Adams
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